The are a number of spectrophotometers or spectrometers that are used to detect the spectral characteristics of a test sample. For example, U.S. Pat. No. 4,330,207 discloses a fluorescence spectrophotometer comprising a light source, an excitation side monochromator which makes light from the light source be subjected to spectroscopic analysis for illuminating as actinic light a sample, a fluorescence side monochromator which makes fluorescence light from the sample be subjected to spectroscopic analysis, a detector which detects light from the fluorescence side monochromator, and a scanning means which adjusts both the monochromators to the wavelengths of the actinic light and the fluorescence light to be scanned. These monochromators are arranged in such a way that one of them is automatically set to the location of the peak wavelength value which is detected by itself through a simple and automatic wavelength scanning operation and then the other is wavelength-scanned for excitation spectrum or fluorescence spectrum measurement. This device is designed to detect a range of wavelengths of photonic radiation and saves in a memory means the wavelength having the higher peak value.
In addition, U.S. Pat. No. 5,194,916 describes a fluorescence spectrophotometer which comprises an excitation monochromatic light generating means for irradiating excitation monochromatic light onto a sample to be measured, an emission monochromator for selecting monochromatic light from fluorescent light emitted from the sample, an emission photometer for generating a primary output signal corresponding to the strength of the monochromatic light selected by the emission. monochromator, a filtering means for eliminating noises from the primary output and for generating a secondary output, the filtering means being characterized by a response value; determination means for determining a content of the sample based on the secondary output and a response setting means for setting the response value of the filtering means based on the primary output. A table includes the strength data of the primary signal and the corresponding response value, which are determined before hand through experiments and in some cases this correlation can be determined by a mathematical formula.
A spectrophotometer including a light source operative to emit a beam of light, an optical system for directing the light beam to a sample to be analyzed, and a detector which detects the intensity of the light beam after the beam interacts with the sample is disclosed in U.S. Pat. No. 6,002,477. The light source is operative to emit bursts of light separated by an interval during which no light is emitted. By way of example, a xenon tube may be used for that purpose. The spectrophotometer measures the intensity of the light beam generated by each burst of light after that beam interacts with the sample. Each such light beam may be divided into first and second parts prior to interaction with the sample, and the optical system is arranged to direct the first part to the sample and to direct the second part to a second detector for conducting a reference measurement. A dark signal measurement may be conducted immediately before or after each burst of light. Thus by having a reference signal determining the noise within the system provides a means for isolating the received signal. However, the determination of the reference signal at the time of scanning of the test sample is critical to the functionality of this system, since “dark noise” can change dramatically over very small periods of time.
This background information is provided for the purpose of making known information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.